DSB Sand Sifter?

[Myka]

Ebola, you could try a single Nassarius snail. That would clean up some detritus without disturbing the sandbed too much. A DSB shouldn't be disturbed much if it is to retain it's nutrient reducing properties.

[Marlin65]

+1 have have three of the bigger ones in my refugium 35 gal and 7-8" of sand and they do a fine job of keeping my sand clean. Some of the small cucumbers might work as well. You don't wand to add anything that is a predator.
To truly get a real live sand bed you have to add real live sand and no you can't get all your organisms from the live rock. Some are just not there unless you get it right from the ocean into your tanks. (those so called live sand bags you get from the store are not the same thing)
You should be able to get a refugium sand bed running fairly well and clean by seeding it from other tanks.
I forgot if you are local but you are welcome top stop by and get a cup from me.

[tlo]

If you dont want a cucumber, get a sand dollar. They are not that common in the pet stores, but if you can find one, do a wonderful job of keeping the sand clean.